How to Repair a Leaking Stopcock in Situ? All aspects of plumbing questions and answers, help, tips and information

[sparky01]

Hi new here and needing some advice.
I know its probably (most likely more like it) a really stupid question but I am not a plumber, never tried to be one and never claimed to be one so figure its better to ask first.

I have a leaking stopcock under my sink. From what I can see (its in an awkward place) it seems to be leaking from the nut that it screws into. I looked up a few links and videos on how to fix it and it seems fairly simple. However none of the vids / info pages state anything about whether you can either change a stopcock or repair a leaking one while ONLY the stopcock is turned off to shut off the cold water. Can I take it off if needs be with only the cold water shut off or do I have to shut off the complete water mains / main stopcock which I believe is in the attic.

It doesn't seem to be a horribly bad leak but I noticed a few days ago parts of my floor were wet for no reason and traced it to this stopcock dripping slowly over time.

So all I need to know is if I need to shut off the mains water supply completely of if turning the stopcock off is good enough for this job.
Thanks for any help

[thedoctor]

The water comes to the main stopcock from outside, not from the loft. It needs to be turned off outside in the road. See our plumbing tutorial videos on our YouTube channel here https://www.youtube.com/watch?v=kjvWEoOjYB4 If you subscribe to our channel you will get notification of the videos we publish every week. The plumbing series should answer all your questions

[htg engineer]

I would try and isolate the water at the external stop tap before attempting to repair the leak, as things can go wrong, even for experienced plumbers.